Background and Aims: High self-esteem is associated with many positive outcomes, including occupational success, healthy relationships, subjective well-being, and academic achievement. Conversely, low self-esteem has been linked to a number of societal problems, including depressive symptoms, poor health, and antisocial behavior. Given its importance, we know relatively little about the development of self-esteem during adulthood and old age, about the factors that promote self-esteem at different stages of the lifespan, or about the long-term consequences of self-esteem for important life outcomes. Aims of the proposed project include: (1) to document age differences in self-esteem across the entire adult lifespan, (2) to test hypotheses about the effects of work, relationship, and health experiences on intra-individual changes in self-esteem, and (3) to examine the reciprocal influence of self-esteem on changes in work, relationship, and health experiences. Methods: The proposed research will use data from the Americans' Changing Lives (ACL) study, a national 3-wave panel study that uses a cohort-sequential design in which individuals aged 25 to 96 were followed longitudinally for eight years (N = 3,617; N = 2,867; N = 2,562). The ACL dataset provides a unique opportunity to delineate the normative trajectory of self-esteem from early adulthood to old age and to examine reciprocal relations between self-esteem and important life experiences. The cohort-sequential design allows us to test whether age-related changes in self-esteem and the antecedents and consequences of self-esteem generalize across multiple age cohorts. Hypotheses will be tested using structural equation modeling with latent growth curves. Significance: The findings will help establish when in the lifespan normative change in self-esteem occurs, provide new knowledge about the conditions under which self-esteem changes, and identify factors that promote healthy self-esteem development. Moreover, the proposed research will test competing hypotheses about the positive and negative consequences of self-esteem and help reconcile conflicting theoretical views about whether self-esteem is a cause or consequence (or both) of important social problems. Finally, by examining patterns of results across developmental periods and across three life domains, we will use the findings to develop an overarching theory of the life course trajectory of self-esteem.